The invention relates to a digital amblyopia image aid system provided with individually adjustable function, more specifically, it relates to the image contrast intensification parameters which can be adjusted by the vision disabled to be suitable for oneself according to the vision degradation degree, to enhance the image contrast information and provide with optimal image effect. The said system can be applied in electronic magnification system, added with internee function, making it become the class instruction reading system for the vision disabled, while the digital signal processor (DSP) is used for outdoors and increasing the convenience, which adds exclusive image contrast intensification function into portable aid to bring more convenience and practicability for the vision disabled.
Most people perceive via sensory organs and communicate with people around them, which makes significant influence on our daily life function. In comparison with the sense of touch, taste and smell, we heavily rely on the function of the sense of sight and hearing much in most function of our daily life. Our sensory function provides with acquired adaptive capability can compensate the minor loss of certain sensation. In general, if one of the both functions is lost, the other one will automatically enhance the function thereof to supply the lost part. While the both are damaged to lose their function, the other remained sense function might be able to use for minor help. When one who unfortunately lose his sensory function, especially the sense of sight and hearing, may result in reducing of life function and quality, particularly in the aspect of communication and message delivery between people, sports capability, works, entertainment, etc. The cause resulting in sensory function losing may originate from congenital diseases, acquired diseases or accidents, etc. Particularly for Taiwan, the society of which steps toward industrialized age, the convenient, effective and cheap rehabilitative aid will become the major factor for increasing production power, activity power and life quality of these people. Thus it is especially important, nowadays, the computer science is getting popular, thus the function of disability aid is gradually toward high-tech application to assist user to recover the proper function on message delivery, exercise, and works safely. Though the object of natural application is to reduce cost through mass production, the aid design should keep in mind the personal usage. Thus the design of a disabled aid should consider individual medical history to make it better, which includes age, type, and degree of sensory lost, and sometimes more important for educated culture experiences.
The definition of vision impairment is based on acuity and field. The acuity of normal humans is typically from 20/20˜20/40, and the field is between about 160˜180 degrees levelly and 120 degrees vertically. If the measured region is proved to be lower than above values, it can be identified as vision impairment. Legally blind is the one whose acuity is lower than 20/200 or field is smaller than 20 degrees levelly after correction. In general, one who is defined as blindness may still be with slight acuity. But whether the residual acuity can be used or not depends on type of vision impairment and occurrence age. However, in quite a few cases, it can be improved through the method of proper illumination condition and glare reduction, etc.
There can be useful vision between totally blind and legally blind. Thus, “low vision” (amblyopia) is the term for one whose visual function is incomplete, but is better than totally blind, according to the definition. Since that how everybody uses vision aid to increase the effect of one's residual vision is related much with the vision impairment condition. For example, occurrence age: vision impairment happened during variant age results in difference in learning ability, thinking mode, concrete and abstract object, skill, concept, etc. The pathological changes of visual field might result from disease, such as macular degeneration induced central field lose will affect the reading ability, whereas the retinitis pigmentosa induced perimeter view loss will have effects on the exercise ability.
Thus, how to effectively apply engineering techniques to design and fabricate aids, which meets the individual situation, thereby increase the effect of residual vision, is a considerable challenge. Therefore, the endeavors in various levels of physiology, pathology, psychology and society must integrate to make better contribution for the engineering efforts Most of the aids use tactile sense or voice to promote the life function of the vision disabled. While the definition of vision impairment includes different degree of low-vision and blind, large portion belongs to low-vision condition. It is generally believed that if better visual stimulus can be provided during early stage, then it might be of great helps for the progress of rehabilitation no matter for the young or old.
The present developed aid system for vision impairment focuses mainly on the function of magnification and view in far distance, which can be achieved with two technologies: optical aids and electronic magnifier. The present development of above two technologies will be described below:
Optical aids: mainly consist of optical system, including special glasses, hand or stand magnifier or telescope system. Most of the system focuses on reading assistance, so the major consideration for design is proper and comfortable reading distance, position and coverage of view. While under the requirement of high magnification, it can only achieve by shorting the distance between objects and lens. However, due to the inverse relation between viewing field and magnification factor, this will also reduce the visual field, which usually results in certain degrees of inconvenience for the user, including inconvenience resulting from body-position adjustment (stooping), insufficient illumination, uncomfortable vision, etc. The same case also exists while using computer screen. Therefore, how to effectively provide full view of learning documents and increase the efficacy of reading speed are extremely important research topics. Thus in some system, controllable scanning platform is utilized, some others use glasses to achieve magnification, far view effect. However, under high magnification factor, the user will feel dizzy, sick (resulting from asymmetry between vestibule system and vision), which commonly exists in magnifier application. Glass-type telescope application generally is suitable for static user (reading or watching TV) and the design of bi-focal lens must be used in motion. While viewing a distant place, the telescope part of the lens must be in the far position. Furthermore, there is auto-focus-changing application at present. The important consideration for the user is on the weight, which is expected to progress with material and electronics technology. As to the improvement and control for illumination, there is battery driven head-illuminating equipment used for improving aforementioned disadvantage while being used in high magnification.
Electronic magnifier and image enhancement: to overcome the problem of high magnification optically, there are a large amount of reading system at present, which use CCTVs to enhance the reading ability of the low-vision. The desktop system mainly consists of video camera, illuminating system and screen, the magnification of which generally can achieve about 50 times. The read papers are put on the x-y dual-axis scanning platform, such that the video camera can easily scan. For most of the system, the required contrast can be adjusted at user's swill to reduce glare, and the scattering problem can also be solved through high-light to be fitted for retinitis pigmentosa, etc. older patient. At present, there are quite a few hand-held electronic magnifier systems being supplied for selection, but which is generally with lower magnification, and even must be used by matching with rehabilitative education to bring the effect into full play. In the present development of visual reality, there is visor or goggle mounted display (CMD) used to substitute for display screen, though the price of which is more expensive and fail to be available to all, it is still with quite a little developing potential. Besides the above striving direction, the vision scientists also try to understand more about the vision system for applying in new generation system design, making the system adjustment not just be limited in magnification and contrast adjustment, which comprise the new development in complicated function parameters adjustment for fitting the vision characteristics of individual vision disabled person and image remapping for fitting the residual view, etc. Briefly, the major object for present low-vision technology aids is effectively using the improvement of contrast and the adjustment of illumination condition, though above described problem can be improved through using the two methods, but the problem about adjustable capability is still waiting until further breaking through.
In view of several above disadvantages about optical aids and electronic magnifier, the inventor devotes in research for improving the imperfection, and bases on the accumulated experiences from engaging in the industry for many years, further develops a digital amblyopia image aid system provided with individually adjustable function, which especially refers to one which can adjust on vision according to individual amblyopia patient, and simulate the image seen by the vision disabled through linear and non-linear method to decide image contrast intensification parameters, and adjust image contrast intensification parameters suitable for the user per se according to user's image intensification effect requirement, which can enhance the contrast information of image and provide optimal image effect, and the said system can be applied in electronic magnification system, added with internet function, making it become the class instruction reading system for the vision disabled, while the digital signal processor (DSP) is used for outdoors and convenience increasing, which adds exclusive image contrast intensification function into portable aid to bring more convenience and practicability for the vision disabled.